1) WordPress creates thumbnails automatically?

For example, a photo gallery page will show small thumbnails of the larger / full-size images you uploaded. Themes will often include the featured image you selected in a predefined image size and location in the webpage.

2) All images must be sharpened after resizing?

This is such a standard process that Photoshop, for example, automatically applies a default amount of sharpening when resizing any image — you must specifically uncheck an option in Photoshop to avoid sharpenning an image during the resize process!

3) WordPress does not sharpen resized images?

I bet that you didn’t know this last one… not many people do. ;-)

WordPress creates several different thumbnail images by default (see your WordPress Settings > Media page for the complete list of sizes) and potentially many more, depending on your chosen theme and active plugins. It’s not uncommon, for example, for WordPress to create a half-dozen or more thumbnail images from a single original / full-size image — and in all cases, WordPress does not sharpen or make any adjustments to the resized image it creates!

But don’t “image optimization” plugins do this?

They don’t — image optimization plugins are designed to create smaller / faster loading images, not better looking ones. And when you share a post / page to social media, you want your social image to stand-out! — fuzzy thumbnails just won’t do, no matter how fast they load on your own site. ;-)

By default WPSSO TIE applies a safe and moderate amount of sharpening to every JPEG image created by WordPress. A Premium version is also available that allows customization and fine-tuning of the ImageMagick image library settings.

Can you spot the difference?

Which image would you click on?

These examples show 150x150px thumbnails (300x300px on high-resolution / retina displays) created by WordPress, with and without the WPSSO TIE add-on. The thumbnails are stretched to fit their container here, so you can clearly see the differences. The same lack of sharpening can be found in all resized images from WordPress, but is most noticeable in the smaller sizes WordPress creates.